Digibird.com
Primer: Seven Quick Steps to Image Processing

You aren't done once you've got a memory card full of
images. Now it's time to prepare them for presentation.
Because birds don't consult you regarding your
photographic preferences or camera settings, your images
will frequently be less than perfect coming straight from
the camera.
One of the strengths of digital photography is the ability
to process your images--correct them, if you will--on your
desktop, where you can instantly see the results. Equally
important, you can easily undo your processing mistakes, and
thus feel free to experiment with your tools.

You will need two types of software to process your images
efficiently. The first is a viewer, an application
that allows you to review a large number of images quickly
at full screen expansion. Such a review is known as a
slide show; a web search on that term will reveal
many software choices available for a nominal fee. Your
camera or computer might well have been bundled with such software.
(Check the manual or camera website.)

The second type is an image processor. The de facto
standard here is one of the variants of Adobe
Photoshop, a stripped-down version of which is often
bundled with the camera or printer; although the
full version is quite expensive (and worth it if you are
serious about fine art digital imaging), the "LE" or
"Elements" packages are available for under $100 USD. This
discussion assumes use of the LE version.

Step 1: Backup!
And do it now! Save your raw camera files
on a separate medium (preferably CD-R). This prevents their
loss by hardware failure or accidental overwrite (the one
processing step that you can't undo). Only a fool would
attempt to manipulate the only copy of a precious
image. You may find it helpful to save images in separate
folders for the dates taken.

Step 2: Select your BEST images
Use your
viewer to select the images that are worth further
processing. There are two criteria for you to consider.
First, is the image detail crisp, with the subject in focus
and without motion-induced blur? Second, is the composition
of the image pleasing, for aesthetic and/or documentary
reasons? The answer to both questions should be "yes" to
merit the effort necessary for further processing. You will
need to be brutally objective with your images; remember
that for every beautiful bird photo you've ever seen
published, the photographer probably rejected 50+
others. Like you, they felt as if they were trying to
choose their favorite child.

Your images will vary in the degree of detail they carry,
and there isn't an objective measure of this. Even in a
sequence of identically composed frames, focus and blur can
change radically as the bird moves, camera shake settles, or
atmospheric steadiness changes. One helpful technique for
selecting those of acceptable detail is to watch a slide
show of the entire day's shoot, without making any notes, to
see what the range of detail is. Once you have an idea of
"good" and "bad", make a careful pass through the list and
reject any photo that doesn't carry an acceptable level of
detail. Take your time doing this. According to tradition,
the eyes of an animal should be in focus.

Once you have a list of detailed images, select those for
which the composition pleases you. Generally, if you have
focused on the head, the depth of field is so shallow at the
focal lengths produced by the camera/scope combination that
the background is beautifully blurred. This means that your
subject will be isolated from distracting background (or
foreground) shapes, so you can concentrate on how well the
bird's beauty and character is revealed.

From this point, all subsequent image manipulation will
require Photoshop. Perform the following steps in the
listed order.

Step 3:Sharpen One of the most useful tools Photoshop offers is
the ability to enhance the differences in luminosity between
related pixels. The Filter-Sharpen-Unsharp Mask
enhances the apparent sharpness of edges between shapes in
the image. This appears to sharpen the
focus of the image, enhancing the level of detail by
reducing blur. Every image can benefit from the
gentle application of Unsharp Mask.

Judiciously applied,
the unsharp mask substantially enhances the crispness of the
image. The best values for the unsharp parameters are somewhat a
matter of trial and error. For detailed
three megapixel images where
the bird occupies a large portion of the frame (and the camera's sharpening
option was turned OFF), typical
values are shown in the window above. Use the preview
function (click the checkbox on and off) to preview the
effect of your settings before clicking "OK".
It's important not to overdo it. Too much
sharpening will enhance the noise or graininess of the
image, especially in dark areas. Further sharpening will
lend an artificial look to the image. Sharpening only enhances the detail
that exists in the image--it can't create detail where it
didn't exist in the original.

Unsharp mask should be applied only once. If you later
decide you've applied the wrong amount of sharpening, start
over with the raw image.

Step 4: Levels
One of the penalties of
photography through a spotting scope is the slow
photographic speed of the system; combined with the
desirability of fast shutter speeds (to freeze motion) and
the noise penalty of high ISO (CCD gain), images tend to be
light-starved.

Fortunately, Photoshop is extremely effective for adjusting
image brightness and contrast. The simplest way to do this
is using the Image-Adjust-Levelscontrols. Upon
selecting this function you will see a histogram which
graphs the intensity level of each of the 256 ( 0 through
255, black to white) gray tones that comprise the image.
This is the same histogram that a Coolpix camera
displays during selected playback modes.
The "RGB" channel combines the individual red, green, and
blue channels.

You will adjust the input levels by moving
the three triangular sliders at the bottom of the histogram. This will
change the tonal balance of your image.
First, adjust the contrast of your image by using the shadow
(leftmost) and highlight (rightmost) sliders. Move the
shadow slider to the right until its level's value is
non-zero, then three more units; if the first value is
non-zero, move the slider to level 3. The effect will be to
deepen the black tones, giving the impression of removing a
light haze. Then move the highlight slider to the left
until the brightest spot on your image is as bright as you want it to
be while retaining detail. This sets
the maximum white level.

Now, if necessary, adjust the overall brightness of the
image by moving the midtone (center) slider left, if the
image requires lightening, or right if the image requires
darkening. This slider adjusts the center of the tone
scale without changing shadow and highlight values; it
allows you to lighten or darken the image without loss of
detail in the shadows and highlights. The midtone value that gives a pleasing image will
usually be in the range 1.25 to 0.90.

Step 5: Color Balance
If your monitor's color balance is set
properly, you set your camera's color balance correctly for
the light (or to "auto"), and you're lucky, the image will
look perfect at this point. However, you might notice that
the image has a slight green or yellow cast to it. Look
carefully at foliage in your image--do the leaves look a bit
sickly? It's always worthwhile to take a long eyes-only
look at your subject so that you remember how the colors
should look. The Coolpix 990 seems a bit strong in the green
channel, so this is the channel you may need to darken
using Levels.

From the "Channel" option on the Levels dialog box, select
the "Green" channel. Now slide the midtone (center) slider
left slightly--decreasing the green content of the
image--until the image color looks correct. Check and
uncheck the "Preview" box to compare the before and after
image; click "OK" when you're satisfied with the result.

Step 6: Dodge and Burn
Bird images often have strong localized
highlights or deep localized shadows. Once the overall
tonal range of the image is set with the levels controls
(step 4), it is useful to make local adjustments to these
areas. Burning, represented by the thumb and finger
circle (a hole to let light onto the print paper in a
traditional darkroom), lets you darken an area defined by
the "Brushes" palette. To burn, activate the "Tool Options"
control, select "Midtones", and set an exposure of about
20-30%. Hold the mouse button down and move the brush (circle)
over the area you wish to darken; choose a gradient brush
(fuzzy edges) of size appropriate to this area.
Dodging, represented by the lollipop-shaped paddle,
operates analogously to lighten a shadow. Both effects can
be overdone, so make frequent use of the "Edit-undo" option
(Ctrl-Z or Cmd-Z) to see the effect on the image. (Note:
undo undoes the effect of only the last mouse click in Photoshop
LE.)

Step 7: Sizing and Saving
Now you need to make a decision about
the presentation of your image. If you intend to archive
and print this image you should crop and size it now for the intended
print size. A detailed image will
look reasonably good on a photo-quality inkjet printer when printed
with a pixel density, measured in dots-per-inch
(dpi), greater than 250.
This implies a maximum print size
of about 8 inches on the long edge for a 3-megapixel image.
A small print with the same number of pixels will always look better than a
big print because the pixel density, or resolution, is higher.

If you want to archive the image now but manipulate or print it later,
save it now in either Photoshop or TIFF format; this assures
that your file will retain the original image resolution and
level of detail. DON'T overwrite your original image to save your work!
Use File-Save As... and choose a naming convention that
allows you to distinguish between original camera files and
manipulated images. For example, if the original file name
is DSCN0001.JPG, you might save the adjusted image as
Da0001.PSD (Photoshop format) for archiving.

Use the Image-Image Size dialog box to
set the size and density. Making sure the "Constrain
Proportions" box is checked and the "Resample Image" box is
UNchecked, set the larger of the Width or Height to 8 inches
(or smaller). Note that a smaller image has a
correspondingly larger resolution; if Resampling is NOT
enabled, the file will retain all the original detail. "Pixel
Dimensions" is the size of the image in pixels--width times height, times
three (for three color channels), not the size of
the file in disk space. Saved Photoshop or TIFF files will be at least the same
size as the pixel dimensions.

If you intend to post your image on the Web or email it,
remember that the resolution of a computer monitor is far
lower than that of a printed page; a screen image holds much
less detail than a same-sized print. This means your images
can be reduced in both image size and file size without apparent
degradation. A useful image size for
screen display has a long edge of about 500 pixels (about 7 inches).
Standard screen pixel
density is 72 dpi, so the pixel density of the image should also be 72 dpi.

In the Image Size dialog, check
the "Resample Images" checkbox--this lets you set resolution
independent of image size--and set the Resolution to 72
pixels per inch. Now set the Print Size: Width or Height to the desired
size and click OK. Note that the on-screen image will get smaller; use the
Magnifying Glass to enlarge it to 100% size. If you need a different size, use Undo
to undo the size change and try again.
Keep in mind that larger images produce larger files, which are slower to
download; the file size will scale with the area (width times height)
of the image.

For Web or email use, save the file in
JPEG format, using File-Save As....
Again: don't overwrite the original image! You might
choose Dw0001.JPG as a naming convention to distinguish this file from an original
camera file. JPEG compression produces much smaller image files than
Photoshop or TIFF by reducing detail, so it should not be
used for archiving your adjusted image (even if the original
is in JPEG format!). When the File-Save As-JPEG
Options dialog box pops up, choose a Quality value no greater
than 7 (higher values produce virtually identical results)
and choose Progressive Scans (allows your image to download
in stages) if that option is available. For reference the "original"
and "final" images below are 500 by
332 pixels (72 dpi), and about 35 kB each. Click on one to decide if the download speed
is "friendly". It would take about 200 times longer to download this file in Photoshop or
TIFF format at full resolution (~7 MB), and 25 times longer to download the original (~1 MB) camera file.

Here are several examples of an image at different levels of JPEG compression. Look
carefully to see the differences, especially around the eye. Compression artifacts are
most pronounced at edges and bright color changes. These are 225 by 150 pixel, 72 dpi images;
uncompressed file size would be 101 kB.
Highly detailed images generate larger JPEG files for a given setting.

JPG=2, 11 kB

JPG=5, 14 kB

JPG=7, 21 kB

JPG=10, 51 kB

This Primer should be considered just a very quick overview of some of the
image processing capabilities of Photoshop; you should use
these guidelines as a starting point for your own
experiments. Practicing your Photoshop skills will improve
them and give you greater confidence in shooting more
challenging situations, since you will better appreciate the wonders
you can produce in your "darkroom".

Many capabilities of Photoshop are beyond the scope of this Primer. For
excellent discussions of more powerful Photoshop techniques, Digibird recommends: